The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
In multi-engine aircrafts, each engine is housed in a nacelle serving at the same time as a support and as a cowl for the engine.
In general, this nacelle is connected directly or via a pylon, either to the wing or to the fuselage of the aircraft.
In addition to housing the turbojet engine, the nacelle may also receive different appended mechanical systems, and in particular a mechanical system for actuating the thrust reverser.
The thrust reverser is a device which allows directing forward the air flow generated by the turbojet engine, thereby allowing to shorten the landing distance and to limit application of the brakes of the landers.
In general, a nacelle has a substantially tubular structure, with an air inlet upstream of the turbojet engine, followed by a mid-section intended to surround a turbojet engine fan, a downstream section integrating the thrust reversal means and surrounding the combustion chamber of the turbojet engine at the same time.
The nacelle further comprises, at its downstream end, a nozzle for ejecting the flow leaving the turbojet engine.
Most modern technologies use bypass turbojet engines; in these turbojet engines, both a hot air flow called primary flow, and a cold air flow called secondary flow are generated via the blades of the fan.
This second flow called cold air flow circulates outside the turbojet engine through an annular passageway also called flow path, this flow path being formed between a fairing of the turbojet engine and the inner wall of the nacelle.
In this type of engine, the thrust reverser, partially or fully obstructs the cold air flow path, in order to redirect this flow toward the front of the nacelle.
There are several different technologies for realizing these thrust reversers.
One technology, which is particularly interesting because it reduces the length of the nacelle and consequently limits both its mass and its drag, consists of movable cascade-type thrust reversers wherein the cascades are housed between the casings and the cowl of the fan, during a direct jet operation of the nacelle.
In this type of thrust reverser, the reversal is achieved by translating the outer cowl with the cascades which thereby get out of their housing and allow directing forward the air flow.
Moreover, there are also two major types of nacelle structures, namely a first type wherein the outer cowl is formed with two substantially semi-cylindrical shaped half-cowls, these two half-cowls being hinged at the upper portion on hinges substantially parallel to the translational direction of the outer cowl.
The connection between the two half-cowls is achieved by locks disposed at the lower portion.
A second type of structure of the nacelle is called integral or O -structure and wherein the outer cowl is formed from a single cylindrical piece.
The present disclosure concerns the field of nacelles of the mentioned first category, commonly called D-structure nacelles, and provides an improvement to the D-structure nacelles and to the movable cascade-type thrust reverser nacelles.
As in all types of nacelles, maintenance operations are to be provided for regularly and in order to do this, it is necessary to be able to access the inside of the nacelle and, for example the turbojet engine, or still the appended devices and in particular the inner structure of the thrust reverser.
In the specific device type within which the present disclosure falls, access to the inside of the nacelle is achieved by performing the unlocking at the two half-cowls enabling a <<butterfly>>-like opening, after having performed beforehand an unlocking between the movable cascades and the half-cowls.
We understand this double unlocking is particularly disadvantageous on the one hand, disconnection of the movable cascades is complicated by a restricted access to the disconnection system and on the other hand, this double unlocking system increases the weight of the nacelle in a detrimental manner; finally, this double unlocking system also increases the dimensions of the nacelle and the associated cowl.